Great circle course computer



Sept. l16, 1952 F. E. VALENTINEA GREAT CIRCLE COURSE CIOMPUTER 2 SHEETS-SHEET 1 Filed DeC. 30, 1949 Inv ent o1- Tf1-ah k E. glalehtr-le,

W mim Sept. 16, 1952 F. E. VALENTINE 2,610,403

GREAT CIRCLE couRsE COMPUTER Filed nec. so; 1949 2 SHEETS- SHEET 2 Invent oT': Trank E. Valentine,

b5 W WM.

H is Attorney.

Patented Sept. 16, 1952 weenera New"Yorkl' ApplicationDecemberBO,

3 CIaiinsl This invention relates to agreat circle cou'rse. computer. and, in. particulan. to` nieclanisrn that" indiate'sat any-stage offa coursealn'gfa great circleroute the,' `exact position of.- aship and 'the` course angle tol be followedlby thev heliri'smanorl. automatic steering.e'quipment'.v v n the navigation of av shipQit .is .necessaryto takel a. fix orithe Vsun vor starsfand.tdetermiiie by' ymeans oi. celestial navigation the location of a` ship at' any. one instant. The .proc'ssfofltaining ones dead. reckoning point involvsithe' use of mathematical. tables. andi' charts. The` computation after aj on. the. star. hasfbe'entaken,y usually requires 4about' llrniriutes. calculation.. isflfrequen'tly repeated and.V a chart' made fromv the. calculations to. determine the. courser of theship. VAfter each i'lxracourse.anglev isthen .computed which directs. the'. sh'i'p'sf. helrnsman as 'to thecourseto be followedf It is not.. unusual thatan hours time be requiredsto solve. thecourseangle problem.

In bad weather, of coursefituis iiapossihle..tof4 determine aposi'tion by celestialnavigatiorrand.` it is then necessary toestimate the course and?. positonof the ship. Naturallyr. this. latter.. method leaves room for considerable-. erron While automatic dead reckoning. devices.. that plot courses.. sailed'- vby ships are.I1 c I, -.r'ieW,.. there has; longbeen need 'in the art-for an autornaticA great circle coursecomputer. thatat all'.' t irnes indicates-the .course angle..to .beffollowed. the hel`msman:.. 7 v

YIt is an.. object .of this. invention toprovidea new. and.. improved. dead reckoning... andfgreat. circlecoursecornputing r'i'evice.l

Itlisv a further object' oflthis;inventioritolprvide an' improvedidead .reolonirg devicewhiell is f. practical and. yet.' does .not.. involveexcessive" costofconstructionl l Itis a still-..furtherobject of this inventionto ,provide a. new.. and'rnprovdl de'adlreclinin andg'reancirci'courscomput matig' acc j. and "which functions" tjlead 'aL-shipt. .its destin' asesinan-y kind ofweather; 1' v Broiajidlinthisfi jftio'n. comprises'ja" g mbar system fprovideidfw rifa" pairor'sefn' 'ci 'ari lipswhchirepi'eseiit mi'dan ffdsf; these hoops are sei'iuredlto rir'g's` h1c de'siite'iA theJ great:A circle course-1th befllbwedto ai determined desti'nfation. y Afterftii. been!v set, the. :hoopnlthat vre'pife's'e'nts the.- p

tions of the ships propeller.. to' indicate?. at times theA position of` the ship; lal'ong. the selected great circle course, andthewangle'; followedeby the.he1msma n..- f

Frank* E; valentine; Schweriner-fm1 Ygjassigjnqiq lv Electric'v Company; acbr'pdratioirfo Frther objects. andadantages of this invenf tiorvvill'v become apparent-...andthe invention. will bl indi-"e cl'arlill. understood' from.. the following.

' description referring; .to the accompanying drawpaticularity inthe .clairxsI annexed'ltoand form?- ing a part ofthis specification.

Referring. to the drawing, Fig. 1` is-a diagrammatidviewiii perspective showing thefunei-onfng l.elementsof this .improved computing device.. While- 2is. ai.'diag/rarnznatie- Viewv indicating-l. theposition ofthe-course rring. for. apre-selected'. course.;

`Iritll drawing.,ali-ring] isr'rivot'ally ysup-jA portedinal stand# A lock screvf 3-ispositionedin .thesta-nd-to secure-'the supporting.. shaft- 4 of the-ringlin any. selected.position. Asuppor-t ring., 5is .pivotallyfsecuredto D-ring- I byears 6. and pins- 1. positioned..90 degrees out of line. with.. sl'afts.4l Alocking yscrew 3 is posi-A tioned in .D-ring-.I to securepins ,T I inany seleeted pdsfon l Support ring. ;.5 is provided with. a. .plurality of disposed...circumferential@ rollers such-.asfl 9 and: I D- which.. are suitably.. spaced and :rotatably =se- A c ured by: means. of:y Vertical shaftsU I I Rollers 1 9.. support1 an innerv ringfv I 2 rto .be .rotatable rela-.- tiveto and i ri a plane-.parallel with support ring.. 5 .whilerollers I supportan outer ring'. I3. so. thatit. `isrotata1ole relative to.v .and` in I aplarie parallel with support ring. Rings4 I2iand l3, .then.,. are rotatable.v iny parallel. planes relative to one another andto support'ring-5 .f

Inner` ring I2 is-provided withan integrallyformed circular hoop I4. which extends*L down- Wardly froinvtlfiering.y Airing-gear I5,provided with-gearteethuI-Ggis securedtohoop"I4.` Gea-ri.. ring I5 extends outwardly-y from hoop I4; and

therefore liesL in aplane yparallely tor-ing.- I2. A motor I'I is` supported yby a bracket I8 v v; hich,v inturn, securedto'supportring; 5.". MotorZ I-"I` drives a= pinionvI 9 i whichv y is in. mesh with gearV teeth IBon gearfringf-l5.` f'

, Asemi-circularYv hoop-,I hereinafter. called. the.

. present meridian" hoop' 20. Vis-.fpivotallyfv mounted'1 tending portion of stand 2 has not been shown, but the stand does continue upwardly to provide a top portion which is an integral part of stand 2. A vertical shaft structure designated generally as 21 is supported from the upper portion 26 of stand 2 and its axis passes through the center of inner ring I2 and outer ring I3.

Vertical shaft structure 21 comprises an inner shaft 28, a central shaft 2'9 and an outer shaft 35. The three shafts are closely interftted but rotatable relative to one another and top portion 2S of stand 2. l A l *Y A globe 3| is suspended vto inner. shaft 28, which will hereinafter be referred to as the globe support shaft. Inner shaft 28 extends through top portion 26 and a bushing 32 which is secured to the top portion 25. through bushing 32, and when it is so desired, set screw 33 can secureglobe support shaft'28 to prevent it from rotating relative to upper portion-25. `Globe support shaft 28 is pinned to a horizontally/,disposed disc v34 which carries a pair of matchedscales 35 and 36V about Vits outer periphery. Since 'disc 34 is pinned to globe supportV shaft'28, there is no relative movement between scales 35 and 36 and globe 3|; consequently, scales 35 and 35 indicate actual meridians on the globe.

l The extension 31 of globe support shaft28 on the upper side 'of top portion 26 carriesV a -gear 38,5 A pinion 39 in'mesh with gear 3Sis carried vby a shaft 40, which is secured to top portion -2'6 but rotatable relative to it. A knurled knob 4| is secured to shaft 40. When knob 4| is turned, the pinion 39 rotates and thus drives gear 38Which rotates globe support shaft Y28.

Central shaft 29, hereinafter called present longitude shaft,` is provided with an arm 42 that carriesa pointer5143 that reads against scale 35 on disc 34. At its lowerl extremity, present longitude shaft 29 is in engagement with presentv meridianhoop 20. Hoop 20 is slidable inra slideway 44positionecl in a block 45 secured to present longitude shaft 29.l A pointer 46 positioned on block indicates the position of present meridian-hoop 20 relative to the block. Present meridia'nvhopeZll carries'a scale 41 graduated to read latitude north and, south of the equator. The sca-le' "reading at the Ymid-point of Vpresent meridian hoop 20' is zero, andv this extends kat the outermost extremitiestd 90` degrees north or sou'thfof thee'quatr.- v f I Outer shaft 30'; hereinafter'c'alled destination longitude shaft, is provided'with an arrn 48 that carriesa pointer 49 ,that reads against scale 36 on' Ydisc 34. The lower eXtermity of the destinationlongitude 'shaft is in engagement'with destination median 232 I-Ioop 23 is slidable in a slidewafiflil,` which is 'positioned in a block 5|, secured lto destination llongitude shaft 30. A pointer 52 indicates the position ofhoop 23 relative to destination longitude shaft 3D. Hoop` 23 carries a scale 53 which is similarv to scale 41 on hoop 29 and reads longitude north and southI of the equator.v lI'he mid-point of hoop 23carries` a Zero mark which indicates the equator. Y

Destination longitude shaft 3D is further provided with ay support 54 which:carries a shaft 55 that is rotatable therein. A pinion 56 and a knurled `knob'51 are secured to shaft 55. Pinion 55 is in engagement with algear sector 58 cut on the outer periphery of hoop A23. By turning knurled knob 51, pinion 59 drives gear sector 58 to move hoop 23 relative to pointer 52 and destination longitude shaft 30.

relative to A 'seti screw 33 extends- In order to set this mechanism for any selected course, it is necessary to provide a structiue for reading and setting the present longitude and latitude of the position of the ship and a structure for reading and setting the longitude and latitude of the destination of the ship. Thegstructure providedfor these readings and settingsV is as follows: Y 7

In order to set the present latitude, a gear sector 59 is secured to one of the supporting shafts 4. A pinion l6|) in engagement with sector 59 is carried by a shaft 5| which is rotatably supportedV (not shown) by stand 2. A knurled knob '62 issecured to. shaft 6|, and when it is turned pinion 66 Idr'ivesgear sector 59 to rotate supporting shafts 4 relative to stand 2. The rotation `of shaft i4 is indicated by pointer 46 reading against scale 41, and the present latitude is thus set.

, In order to set the present longitude, assumingthat pins 2| on hoop 20 are in axial alignment with pins 1 of D-ring I, discv 34 is rotated by means'of Vknurled knob 4| rotating pinion 39 which drives gear 38 and globe support shaft 28. Since disc 34 is securedV to globe support shaft 28, dial 35 is moved relative to pointer 43 until the predetermined setting is reached.

Ino'rder to set theY latitude of destination, knurled knob 51 is rotatedto turn pinion 56 which drives gear sector 58 moving hoop 23 relative to pointer 52 on block 5I until the predetermined setting is reached. Y

In order to set the longitude of destination, gear teeth 63 are provided on the outer periphery of outer ring I3. Support ringV 5 carries an ear 64 which rotatably supports a shaft 65 on which there is mounted a pinion 66. A knurled knob 51 is secured to shaft 65 and when it is'rotated, it turns pinion 66 which drives gear teeth 63 and turns outer ring I3 relative to support ring 5. As outer ring I3 is rotated, hoop 23 rotates with it andturns destination longitude vshaft 30 about globe support shaft 28. As destination longitude'shaft-3D rotates, arm 48 and pointer 49 move relative to'scaley 36 until the predetermined setting is reached.

' In accordance with that which has heretofore been disclosed, D-ring I is pivotable with supporting shafts 4 relative to stand 2. Support ring 5 is pivotable ywith pins 1 relative to D-ring |.y

Present longitude ring I2, and destination longitude ring I3, are rotatable relative to one another and relative to support ring 5. This structurevpermits support ring 5, present longitude ring I2, and destination longitude ring I3 to describe a great circle course from a present position to a selected destination. Y

' In order to have the three parallel rings 5, I2 and I3 describe the desired great circle course, it is necessary first to have'all the set screws loosened,v then pins 2| on present meridian hoop 2|]v arejplaced in axial alignment with pins 1 in D-ringil'. While it is not shown in the drawings, a releasable pin detent arrangement is provided to .properly` position present longitude ring I2 relative 'to support ring 5 iny order to have pins 2| Ain axial alignment with pins 1. f

Knurled knobY 62 is turned to rotate shaft 4 relative to-support 2, which raises or lowers pins 1 according to the direction of rotation of knob -62 and moves present meridian hoop 20 relative to present longitude shaft 29 and the present latitude is set-in by aligningV pointer 46 with -scale 41 onl hoop 20.

alwaysV with pin 2I in. axial alignment. withpn. 1'., it. is necessary to move globe support shaft. 28`zandlglobe 3| relative to Ypresent meridian l2li until .the pointer 43 reads the proper degree ,of present 4longitude on scale 35.v To .do this, knurledgknob 4I`..is turned to drive Vgear SSand f globe support'shaft 28. Disc 34, which is pinned to. globe'. supporti. shaft 28,. is turned. with, the shaftruntil the present meridian degreeon scale 35: is aligned Vwith pointer 43 on arm ll2. To reiterate, for every present longitude setting,

pointerllSA is.` in the sameposition and scale 35 must: bel moved relative to vpointer 43. When the Vproper meridian degreeon ldial 35 isin alignmentv with pointer y13,v the' corresponding merid-l ian on.globe.3l is under present meridian hoop 20;. `Set screw 33 is then tightenedA and globe,

support shaft A28 is locked in place. 4 f

v. The destination latitude is ,then set -by turning knurled knob-51 which drives pinion 56 and gear:

sectorA 58 until the selected latitude onscale53 is,v inalignment with pointer 52.,secured to des-v tinationglatitude shaft 3i).l Pins 24 are thus raised or lowered, depending upon thepreselected destination latitude.

Destination longitude hoop V23` is then moved until5it-correspondswiththe meridian of deshoop 2Ilfzisgat right angles Lto thezplane; or present longitude ring. I 2,.Y the phase .angle between the stator and rotorginlgenerator 'I lA is zero1andcon'.

sequently,.'a vzero voltage is producedy by; thegenerator.f, v

The voltagefproducedfby generator 'It can; be' transmitted` to anindicator infront of. the helms man,'.or"it:canbe. employed to operate automatic,-

steering equipment withina ship..

As. has been.; previously described, a .bracket t3;

is securedfto support ringg and Vpositions, amotor' I1 vand a'pinionl 9 in engagement with gearfteeth. Y I8 on gear ring I5'- Aspinion. I9 turns, 'it drives gear ring t5.; Since geai' ring I5 is fixed? relative to lpreesnt longitudering I '2, pins v2|.-positioned thereon and 'present meridian hoop Zi'imoveY with'.

gear-ring 15;! Present meridianhoop 20?,.in turn, through its engagement with slideway Mein block 45 rotates presentlongitude shaft'- 29.r 'Ar-m: 42:' and Apointer 13,'whicharesecured to presentg longitude shaft,- rotate relative to scale; When pinion I9, then, is` rotated clockwise (viewed from motor" Il), arm `I2r andipointer- 32 move across scale135ftowardsA arm i8 and pointer'lil,

r which are-secured tothe: destination longitudel shaft 3th Asarmr42 and vpointer 'A3-move towards Y the destination'point, present meridian hoop 210' tination. This is,y done by turning knurled knob 61; which drives-.pinion 63v andgear teeth 63.

Pins 24- are, consequently, moved to the yright or. to thefleft and hoop 23,because' of its contact` with slideway 5B in block 5|, rotates destination longitude shaft 30 and the arm" t8 secured thereto. Knurled knob 61 is rotateduntil pointer 4.9. isv in alignment with destination longitude on scale 36- on disc-3I-.v Whenl this` setting is reached,

destination meridian hoop 23 yisover the meridian; lon' the'globe that` passesthrough the destination point.

It should be pointed out at this time that globe 3Iis not ay functioningrv element of .thisy mechanism'.` Its purpose -is merely to visually' interpreti thesettingsthat are made on. thevarious scales.l It is not intended that any accurate readings be. obtained from globeV 3I, but itis obvious that theglobe will be of assistance in telling vwhether, the protracted course passes 'through' any islands.

or-other obstructions.

.I When-these settings have-been1made,the three. parallel rings 5, I2 and I3, describe the initial.

great :circle course tobe followed to reach the selected destination. The'angle 'I2 between present meridian hoop 20 and present longitude ring..

lz-istheinitial courseangle .for the'great circle course to be followed. VIf the helmsmansets his steering apparatus at this angle, he startsy along the-greatcircle course to the destination. As willgbe hereinafter described, the course angle changes,continually;` consequently, the helmswith this vcourse angle.

man continually resets hiscourse' in. agreement moves towards destination meridian hoop 23Tfand= the course angle 'I2 increases orvdecreasesdee- .In-,order to vfacilitatethe reading of thetcourseV angle. thus determined, a gear sector 613 isse-y This gear.

curled to present meridian hoop 2li. sectorfisrotatable with hoop 29 about pins 2l as=an axis. Gearsector 68 is in engagement with a v'gear'il secured 'to ra shaft 10 of'aselsyn'generator TI, which, in*v turn, is securedfto gear ring l.5','fin integral part of f present longitude ring I 2. Asffgean 6B is driven, it'chan'ges the @phase-angle between the stator 'and the'rotor of' the` fselsyn generator 1l thus'incre'asing-or :decreasing the voltageoutput of; the'gen'erato'r, depending upon' whether thephase angle isincreased orA de` creased: @Whenthe-plane of presentv'meridian' pendent on whether pins y2| move downwardly or upwardly towards pins 24.1 That is, iffthe course angle 72 as originally set, is less than 90) degrees, outer pin 2l is-below pin 24` and as present meridian hoop moves towards destination meridian hoopv 23 the course angle graduallychanges untilv it is inalignrn'ent when present meridian hoop 20 isYdirectly-under destination meridianhoop 23. Inversely, kifouter pin`2| is aboveepin's 2d, then -oourse ang-le l2 isgreater'than degreesand as present meridian hoop .20 vmoves towards destination meridian hoop 23, the courseY angle gradually changes until it is in :alignment when present meridian hoop=2ll is directly under destination meridian hoop l23.' 'Y

In order for this mechanism to be automatic, it is necessary to have present meridian ring 29 correspond with the present meridian ofthe ship at any instant; consequently, it is desirable tov translate the distance'traveledby-the ship into' al movement of present'longitude ring I 2.- Atffpriesent, the best method of determining distance trav-- eled'by a ship is through measurement of its propeller revolutions. Accordingly, a gear i3 is arranged to be driven-by av propeller shaft "Ill: Gear I3 is secured to a shaft 5-ofa generator 16.. -Suit-H 1 able wiring is used to connect generator -litomotori?.Vv With this arrangement, the rotation ofv propeller shaft 'I4 produces afvoltage in generator 'I6 that isemployedto drive motor I'I and pinion I9. ASuitable gear reduction units- (not shown) must 'be used between? propeller shaft 'I4 and generator 'It in order to properly translate the ship.

Before the operation of this invention is described;arefere'nce'is made to Figf2vwhich gives a simpler indication of what takes place in the structure above described. Fig'. 1, in order to clearly indicate the operating parts, it was necessary to set a great circle course along the equator; consequently, course angle 72 for that particular setting Vwould remain. 90 degrees .at all times. `Fig. 2 which does not disclose an operating .drawing shows theY planeof rings I2 and I3 when the ship is to follow agreat circle course from` a point north of the equator westwardly across the equator to a point south of it. In Fig. 2, supporting shafts 4 are shown positioned in stand 2 and supporting D-ring I. Pins pass through D-ring I to'pivotally support destination longitude ring I3. Present longitude ring I2 and destination longitude ring I3 are indicated to correspond with those shown in Fig. 1. Outer pin 2| and present meridian hoop 20 indicate the present position of the ship above the equator. Pin 24- indicates thedestination of the ship while present longitude ring I2 and destination longitude ring I3 are parallel and the two of them describe the great circle course to ybe followed from pin 2| to pin ,24. Course angle 'I2 is indicated between present meridian hoop' 20 and present longitude ringlIZ. As pin 2| moves towards pin 24, course angle I2 gradually decreases until it is in alignment when present meridian hoop 20 is under destination meridian 24. Y

In the operation of this device referring again to Fig. 1, pins 2| are rst aligned with pins l. Then, a setting is made of the present position and of destination position as has been heretofore described. Proper setting 4gives a course angle 'I2 lwhich is transmitted by selsyn vgenerator Il to the helmsman-*or to automatic steering equipment. As the propeller of the ship rotates, propeller shaft I4 drives gear I3 and generator 'I6 to produce a voltage that drives motor and pinion I9. 'I'he rotation of pinion I9 drives present longitude ring I 2 and present meridian hoop 20 and pin 2| follows a pre-selected great circle course to the destination. Y

In order to simplify the description of this invention, it was necessary-to give a schematic indication of the functioning elements. Obviously, a careful machining and Vernier scales are required for accurate settings, but there is no reason why these parts cannot be built by a skilled machinist.

This invention is primarily a great circle course computer and, as such, is a great time saver in that it indicates a great circle course angle to be followed to a destination without mathematical calculations. With automatic operation of this invention, the course angle is continually indicated. Without automatic operation, the course angle to be followed is indicated each time the computing device is reset after a x has been made to determine the present position of the ship.

VModifications of this invention will occur nto those skilled in the art and it is desired to be understood, therefore, that this invention is not to be limited to the particular embodiment disclosed, but that the appended claims are meant In the structure inv pivot point for pivotally supporting sai'dpresent longitude hoop on said present latitude ring, means including a pivot point for pivotally supporting said destination longitude hoopon said destination latitude ring, means for supporting said rings in the same plane, means mounting said rings for movement relative to one another inv said plane, a globe simulating the earth and mounted within said rings for rotation about an axis representing theearthspolar axis, a shaft disposed in alignment with said axis, said hoops intersecting at said shaft, means for guiding said hoops at said shaft, means mounting said hoops for rotation about'said shaft, means for adjusting said hoops to vary the displacement of 'said pivot points from said shaft, means including scales for adjusting the present latitude ring and Ypresent longitude hoop to have the pivotal point connecting them represent a presentV position on the earths surface, means including scales'for" adjusting the destination latitude ring and destination longitude hoop to have the pivotal point connecting them represent a destination position on the earths surface, and means for measuring the' angle between said present longitude hoop-and the plane of said rings, said angle being the great circle course angle to be followed from the'v ent position to the destination position.

2. A great circle course computing instrument comprising a present latitude ring, a' present longitude hoop, a destination'latitude ring, a destination longitude hoop, means' including a pivot point for pivotally supporting said present longitude hoop on said present latitude ring, means including a pivot point for pivotally supporting said destination longitude hoop on said destination latitude ring, pivotal means Vsupporting said rings in the same plane for rotation about a diameter thereof, means mounting said rings for movement relative to one another in said plane, a xed shaft representing the earths polar axis, said hoops *intersecting at said shaft, means for guiding said hoops at said shaft, means mounting said hoops for rotation about said shaft, means for adjusting said hoops to vary the displacement of said .pivot points from said shaft. means including scales foradjusting the present latitude ring and present longitude hoopto-have the pivotal point connecting them-represent a present position on the earths surface', means including scales for adjusting the ,destination latitude ring and destination longitudeV hoop to have the pivotal point connecting them Vrepresent a destination position on the earths surface, and means fixed to and movable with said present longitude hoop for measuring the angle between said present longitude hoop and the plane of said rings, said angle being the great circle course angle to be followed from the present position to the destination position. t

3. A great circle course computing instrument comprising a present latitude ring, a present longitude hoop, a destination. latitude ring, a destination longitude hoop, means including ,a pivot point for pivotalh7 supporting said present longitude hoop on said present latitude ring, means includingA a pivot point for pivotallysupporting said destination longitude hoop on said destination latitude ring, means for supporting said rings Yin, the same'v plane, means mounting said rings for movement relativeto one another' in said plane, aglobe simulating.'v the earthand mounted Withinsaid rings for rotation about an axis representing gthe earths polar axis, Va shaft disposed in alignment with-said axis, said hoopsv presintezgsecting at said shaft, means for guiding said ent loigitude hoop to have the pivotal point conv necting them represent a present position on the earthsv surface, means including scales for adjusting the destination latitude ring and destination longitude hoop to have the pivotal point connecting them represent a destination position on v the earths surface, and means xed to and movable with said present longitude hoop for measuring the angle between said present longitude hoop and the plane of said rings, said angle being the great circle course angle to beiollowed from the present position to the destinationlposition.

FRANK n". VALENTINE.,

REFERENCES fV The following references are 'of record in the le of this patent: UNITED STATES PATENTS Number Namev x Date Burns Jan. 31, 1933, Sjostrand lOct.,17, 1933 Davis Nov. 26, 1935 Harris Feb. l5, 1938 Graves Nov. 17, 1942 Vielehr et al. Feb. 6, 1945 

